Cathodoluminescence (CL) and photoluminescence (PL) of nickel oxide (NiO) have been investigated. The observed emission bands in the visible and near infrared spectral ranges are attributed to Ni2+ intraionic transitions. Some of the features observed in the CL spectra recorded from vacuum annealed samples are tentatively attributed to electronic transitions involving defect‐induced states located inside the charge‐transfer gap of this transition metal oxide.

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which the metal complexes 11 can be obtained. The reactions of 9 with ethoxyacrolein to give dihydrotetraaza[l4]annuiene tetra~arbonitrile"~] and of 9 with 1,3-diketones to give diazepines were first reported more than a decade ag0.1~~1

ZnTe single crystals grown by the cold travelling heater method have been investigated by means of photo-and cathodoluminescence. The spectral region covered in this work ranges from 2.48 eV (500 nm) which corresponds to band-edge emission to 0.62 eV (2000 nm). Visible and infrared cathodoluminescence images have been recorded, and the influence of extended defects on the observed luminescence has been studied.

Luminescence emission of nanocrystalline silicon films has been studied by cathodoluminescence (CL) in the scanning electron microscope. As-deposited films show a dominant band at 400 nm as well as a band centered at about 650 nm. CL spectra of porous silicon samples also show emission at 400 nm. Spectral changes induced by annealing and implantation treatments of the films suggest that the presence of nanocrystals is the origin of the observed CL.

The effect of the addition of Bi and Mn on the photoluminescence from ZnO ceramics has been investigated. The effect of the presence of impurities on the green luminescence band can be compared to the effect of oxidizing treatments. A narrow green band has been observed in Mn-doped samples.

Changes on the defect structure of Bi12GeO20 (BGO) and Bi12SiO20 (BSO) crystals induced by thermal treatments and laser irradiation have been studied by means of cathodoluminescence in the scanning electron microscope. The results have been compared to those previously reported for untreated and electron irradiated samples and recombination mechanisms responsible for some of the observed luminescence bands are discussed. Annealing of BGO samples causes the appearance of a new luminescence band at about 390 nm. The centers responsible for this band decorate the deformation slip bands in quenched BGO as observed in the cathodoluminescence images. The emission observed in BSO in the same spectral range is quenched during the annealing treatment. The annealing induced reduction of Bi ions to metallic Bi appears to be related to the quenching of a band at 640 nm observed in untreated samples.

Cathodoluminescence and photoluminescence of Bi 12 SiO 20 and Bi 12 GeO 20 samples are studied. Both kinds of samples show a dark orange central part or core. Emissions in the blue, green, and red spectral regions are observed. The 640 nm band is the predominant feature in the core emission. The evolution of this band during electron irradiation suggests possible emission mechanisms. In addition, two infrared emissions at about 915 and 1390 nm are detected.